Managing Anticoagulation in the Perioperative Period
from the ACCP Guidelines, 9th Ed.
The ACCP‘s new 9th edition of their authoritative clinical practice guidelines for prevention and treatment of venous thromboembolism (VTE) were published in February 2012. PulmCCM is not affiliated with ACCP. These summaries are only appropriate for those who have read and are familiar with the original document, which is linked below. (See also “Preventing DVT-PE in hospitalized nonsurgical patients” and “Initial treatment of DVT/PE: How to start and manage warfarin/coumadin“.)
Here we review the section on managing anticoagulation in the perioperative period for patients undergoing surgery. This section of recommendations apply to patients taking daily warfarin/Coumadin, aspirin, or other anticoagulants as treatment for deep venous thrombosis (DVT), pulmonary embolism (PE), atrial fibrillation (A-fib) or other conditions.
The New England Journal also published an important review on this topic; here’s the PulmCCM commentary.
When should a patient stop warfarin/Coumadin prior to surgery?
The ACCP advises to temporarily stop warfarin/Coumadin beginning about 5 days before surgery (Grade 1C: strong recommendation based on consensus opinion/weak evidence).
When should a patient resume/restart warfarin/Coumadin after surgery?
Restart warfarin/Coumadin approximately 12-24 hours after surgery — the evening or next morning following the operation (Grade 2C: suggestion based on consensus opinion/weak evidence). This assumes there was adequate hemostasis achieved and no evidence of ongoing bleeding.
For patients with mechanical heart valves, venous thromboembolism, or atrial fibrillation, when should “bridging therapy” with heparin or another shorter-acting anticoagulant be used to minimize risk of thromboembolism perioperatively while interrupting warfarin/Coumadin?
- The ACCP suggests against bridging therapy in patients at low risk for thromboembolism with mechanical heart valves, VTE, or atrial fibrillation. (Grade 2C: suggestion based on consensus/weak evidence)
- Patients at high risk for thromboembolism should receive bridging therapy (Grade 2C);
- Patients at intermediate risk should be considered on a case-by-case basis for bridging anticoagulation, according to risk of surgical bleeding and the risk of thrombosis. (Grade 2C).
They provide a table with a risk-stratification scheme, which boils down to this:
- DVT/PE low risk patients are > 12 months out from their last DVT/PE and have no other major risk factors (mainly thrombophilia or cancer)
- Atrial fibrillation low risk patients have CHADS2 scores 0-2 and no prior history of stroke/TIA.
- Mechanical valve low risk patients are those with bileaflet aortic valves with no atrial fibrillation, and no other risk factors for stroke (diabetes, hypertension, age > 75, etc.)
Anyone else is at least at intermediate risk for thromboembolism during interruption of warfarin/Coumadin therapy, and deserves strong consideration for bridging anticoagulation.
For patients receiving high-dose intravenous unfractionated heparin as bridging therapy, when should the heparin infusion be stopped prior to surgery?
ACCP suggests stopping the heparin infusion 4-6 hours prior to surgery, no closer. (Grade 2C)
For patients receiving low-molecular weight heparin (e.g., enoxaparin/Lovenox) as bridging therapy, when should the last dose be given prior to surgery?
ACCP suggests giving the last dose of LMWH (e.g., enoxaparin/Lovenox) 24 hours before surgery. (Grade 2C)
When should enoxaparin/Lovenox as bridging therapy be resumed after surgery?
- When using low-molecular weight heparin (e.g. enoxaparin/Lovenox) as bridging therapy, resume it within 24 hours after surgery in patients undergoing surgery with average risk for postoperative bleeding (Grade 2C)
- For patients undergoing surgeries with higher risk of postoperative bleeding (see below), wait 48-72 hours before restarting enoxaparin/Lovenox as bridging anticoagulation (Grade 2C).
Surgeries with higher risk of postoperative bleeding include (but aren’t limited to):
- Urologic surgery including prostate surgery, kidney biopsy or nephrectomy;
- Pacemaker/implantable cardioverter-defibrillator placement;
- Resection of colon polyps, especially large sessile ones;
- Surgery on blood-filled organs like the liver, kidney, and spleen;
- Joint replacements, major cancer resections, and reconstructive plastic surgery;
- Intracranial, cardiac, or spinal surgery.
For people undergoing major surgery, or minor dental or dermatologic procedures or cataract surgery, how should warfarin/Coumadin and aspirin be managed?
These are all suggestions based on consensus/weak evidence (Grade 2C):
- For people undergoing minor dental procedures, either stop warfarin/Coumadin 2-3 days before the procedure, or continue it throughout and use an oral prohemostatic agent.
- For minor dermatologic procedures or cataract surgery, continue warfarin/Coumadin and work on attaining local hemostasis.
- People taking aspirin as secondary prevention for cardiovascular disease are at higher risk for cardiovascular events; they should continue taking aspirin (don’t interrupt therapy) prior to major or minor surgery.
- Those at lower risk (those taking aspirin as primary prevention of cardiovascular disease) should interrupt aspirin 7-10 days prior to major or minor surgery.
- Those taking both aspirin and an additional antiplatelet agent like clopidogrel (Plavix) or prasugrel (Effient) who are undergoing CABG bypass surgery should continue aspirin and stop the additional antiplatelet agent 5 days before surgery.
Notably, the ACCP largely shied away from making recommendations about interrupting clopidogrel/Plavix or prasugrel/Effient prior to major or minor surgery. Anecdotally, interventional pulmonologists consider Plavix to cause much more significant intraprocedural bleeding compared to aspirin.
For people with coronary artery stents taking both aspirin and clopidogrel/Plavix or prasugrel/Effient, how should surgery be planned (or delayed)?
- After placement of a bare-metal stent, defer surgery for at least 6 weeks (Grade 1C: strong recommendation based on consensus / weak evidence);
- After placement of a drug-eluting stent, defer surgery for at least 6 months (Grade 1C).
- If someone needs surgery before these safety-timeframes have elapsed, ACCP suggests continuing both aspirin and clopidogrel/Plavix or prasugrel/Effient around the time of surgery (Grade 2C; suggestion based on consensus/weak evidence).
The ACCP makes caveats throughout this recommendation document emphasizing that the patient’s personal preferences should be discussed and considered in medical decision-making, with statements to the effect of “if a patient is particularly averse to bleeding, the risk of bleeding should be considered more highly than the risk of thromboembolism.” This is reasonable, but could easily become a cop-out or abdication of responsibility by the doctor. You, the physician, have seen and managed bleeding complications from anticoagulation; the patient is usually operating off rumors and nebulous fears. It’s the doctor’s job to make sense of the situation, synthesize the risks of various approaches, then to recommend the best possible treatment course — not to interrogate a fearful, inexperienced patient in the midst of a serious illness about her relative aversions to harm from bleeding vs. thromboembolic complications.
Douketis JD et al. Perioperative Management of Antithrombotic Therapy. Antithrombotic Therapy and Prevention of Thrombosis, 9th ed: American College of Chest Physicians Evidence-Based Clinical Practice Guidelines. CHEST 2012;141 (2 suppl): e326S-e350S.